Date: Mon, 12 Jan 2009 18:39:13 +0100 From: Mateusz Guzik <mjguzik@gmail.com> To: Alexej Sokolov <bsd.quest@googlemail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: panic by unlocking of mutex in KLD Message-ID: <20090112173913.GA2102@skucha> In-Reply-To: <671bb5fc0901120819q65969961v723807bcb7ad5a96@mail.gmail.com> References: <20090112134726.GA2988@debian.samsung.router> <20090112141029.GA31108@skucha> <671bb5fc0901120819q65969961v723807bcb7ad5a96@mail.gmail.com>
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On Mon, Jan 12, 2009 at 05:19:56PM +0100, Alexej Sokolov wrote: > 2009/1/12 Mateusz Guzik <mjguzik@gmail.com> > > Mutexes have owners. It panics on loading because processes cannot > > return to userland with locks held. > > i am not sure about it. Some time ago i implemented a charecter device with > two syscalls: write, read. "write" lock the mutex and "read" unlock it. The > user space programm opens device, then mekes "write" (mutex will held in > kernel), goes back to user space, then makes "read" (mutex will unlocked in > kernel) and it all run without panic. If needed i can post the source code. > Do you have kernel compiled with WITNESS? At least on -CURRENT the kernel panicked like this (while loading your module): System call kldload returning with 1 locks held -- Mateusz Guzik <mjguzik at gmail.com>
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